Paced P-wave duration as a significant predictor for atrial high-rate episodes in patients with cardiac implantable electronic devices

Background Atrial pacing (AP) can unmask or aggravate a preexisting interatrial block (IAB). The aim of our study was to determine whether AP is associated with the development of atrial high-rate episodes (AHRE) during follow-up. Methods Patients with dual-chamber cardiac implantable electronic devices (CIEDs), no previous documented atrial fibrillation, and with a 6-month minimum follow-up were included. In all patients, sinus and paced P-wave duration were measured. AHRE was defined as an episode of atrial rate >= 225 bpm with a minimum duration of 5 min, excluding those documented during the first 3 months after implantation. Results A total of 220 patients were included (75 +/- 10 years, 61% male). After a mean follow-up of 59 +/- 25 months, 46% of patients presented AHRE. Mean paced P-wave duration was significantly longer than the sinus P-wave duration (154 +/- 27 vs. 115 +/- 18 ms; p < .001). Sinus and paced P-waves were significantly longer in those who developed AHRE (sinus: 119 +/- 20 vs. 112 +/- 16; p = .006; paced: 161 +/- 29 vs. 148 +/- 23; p < .001). A paced P-wave >= 160 ms was the best predictor of AHRE, especially those lasting >24 h (odds ratio [OR] 4.2 [95% confidence interval (CI)] [1.6-11.4]; p = .004). Conclusions AP significantly prolongs P-wave duration and is associated with further development of AHRE. A paced P-wave >= 160 ms is a strong predictor of AHRE and should be taken into consideration as a new definition of IAB in the presence of AP.